public void DerivativeTest3()
{
// cos(2x)
Number num = new Number(2);
Variable x = new Variable("x");
Mul mul = new Mul(num, x);
IExpression exp = new Cos(mul);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("-(sin(2 * x) * (2 * 1))", deriv.ToString());
num.Value = 7;
Assert.AreEqual("cos(7 * x)", exp.ToString());
Assert.AreEqual("-(sin(2 * x) * (2 * 1))", deriv.ToString());
}
public void CosDerivativeTest3()
{
// cos(2x)
var num = new Number(2);
var x = new Variable("x");
var mul = new Mul(num, x);
var exp = new Cos(mul);
var deriv = Differentiate(exp);
Assert.Equal("-(sin(2 * x) * 2 * 1)", deriv.ToString());
num.Value = 7;
Assert.Equal("cos(7 * x)", exp.ToString());
Assert.Equal("-(sin(2 * x) * 2 * 1)", deriv.ToString());
}